How Ebola Works

Fever is one of the first symptoms of Ebola. Here, a tracing coordinator checks the temperature of a 2-month-old in Liberia suspected of having Ebola in 2014. John Moore/Getty Images

If you've seen the movie "Outbreak," you probably associate viruses like Ebola with massive bleeding coming out of all orifices of the body. While this isn't completely untrue, the actual symptoms of Ebola are not usually that macabre.

When Ebola enters a human it hangs out seemingly harmless for two to 21 days (typically four to 10), until the symptoms start appearing. First come the fever, chill, headache, muscle and joint aches, and tiredness. At this point, unless there is a known outbreak, the disease can often be confused for many other types of illnesses. And given the most common location of infection is in Africa, malaria is often the first disease that health care workers diagnose.

But then the disease quickly takes a turn for the worse. Patients start complaining of bloody diarrhea, severe sore throat, jaundice, vomiting and loss of appetite. When symptoms have been present for five days, about half of Ebola victims will develop a rash on their trunk and shoulders [sources: Groseth, Smith]. And after this it can get really ugly.

While massive bleeding is actually rare, one of the prominent components of this infection is that patients start to hemorrhage. Their blood starts to clot all throughout their bodies and that quickly exhausts the supply of proteins that handle clots. So that means when tissue damage occurs in other parts of the body, those proteins aren't available to do their clotting work, resulting in uncontrolled bleeding. Now this happens for only about 50 percent of patients, and the uncontrolled bleeding is mostly internal, in the gastrointestinal tract [source: Feldmann]. So while massive bleeding may occur from other parts of the body, it's pretty uncommon.

All of this trauma very quickly adds up to a bad outcome for many patients. For fatal cases, death occurs six to 16 days after the onset of symptoms. Generally that death is not a result of the hemorrhaging, but from multi-organ failure or shock [source: CDC].

Ebola acts quickly, but causes a lot of pain and suffering in its victims during that time. Since treatment options are often unavailable in outbreak areas (more on that later), it's safest to just stay away from the virus. Read on to learn what we know about how it started and how it spreads.

Other Hemorrhagic Fevers

While Ebola is the best-known and most deadly of hemorrhagic fevers, it's by far not the most common out there. A small handful exist, including some well-known diseases such as dengue fever and yellow fever. These hemorrhagic fevers are largely found in tropical areas of the world, and the viruses are known to be carried by ticks, mosquitoes and rodents. Fatality rates vary with death rates as low as 1 percent (Rift Valley fever), all the way up to 70 percent (Crimean-Congo Hemorrhagic Fever) [sources: Mayo Clinic, Smith].